Aplacophora

Taxobox
name = Aplacophora
regnum = Animalia
subregnum = Metazoa
branch = Bilateria
phylum = Mollusca
classis = Aplacophora
subdivision_ranks = Subclasses and families
subdivision =
*Subclass Chaetodermomorpha (Caudofoveata)
** Chaetodermidae
** Falcidentidae
** Limifossoridae
** Metachaetodermatidae
** Prochaetodermatidae
** Scutopidae
*Subclass Neomeniomorpha (Solenogastres)
** Acanthomeniidae
** Amphimeniidae
** Dondersiidae
** Drepanomeniidae
** Epimeniidae
** Gymnomeniidae
** Hemimeniidae
** Heteroherpiidae
** Imeroherpiidae
** Lepidomeniidae
** Macellomeniidae
** Meiomeniidae
** Neomeniidae
** Perimeniidae
** Phyllomeniidae
** Proneomeniidae
** Rhipidoherpiidae
** Rhopalomeniidae
** Sandalomeniidae
** Simrothiellidae
** Strophomeniidae
** Syngenoherpiidae

Aplacophora is a class of small, deep-water, exclusively benthic, shell-less marine mollusks found in all oceans of the world. The class comprises 28 families and about 320 species. Aplacophorans are mostly very small (no longer than 5 cm), cylindrical and worm-like. Some species however can reach a length of 30 cm.

Habitat

Aplacophorans mainly burrow into the substrate in water regions deeper than 20 m. These species may reach densities up to 4 or 5 specimens per m².

Taxonomy

This class was once classified as sea cucumbers in the echinoderms. In 1987, they were officially recognized as mollusks and given their own class.